Yarn transfer method in an automatic take-up motion

ABSTRACT

In an automatic take-up motion of peripheral drive turret type, a method of automatically transferring a yarn from a first bobbin on which said yarn has been being taken-up to a second unwound bobbin on which said yarn is to be wound subsequently, is disclosed herein. These first and second bobbins are mounted on a turret mechanism so as to be readily exchanged in position by rotating said turret mechanism. This novel yarn transfer method consists of the steps of driving said first and second bobbins with independent electric motors, lowering a traverse speed of the yarn to a speed that is most suitable for formation of a transfer tail, displacing a traverse cam roll with a pneumatic cylinder or other known means so as to make the yarn contact with a yarn grasping device provided at an end of the bobbins or on a bobbin holder and to make the yarn grasping device grasp said yarn, cutting off the yarn between said yarn grasping device and the fully wound first take-up bobbin by means of a cutter associated with said yarn grasping device to take-up the yarn on the second unwound bobbin, restoring the traverse cam roll to its normal position simultaneously with the formation of the transfer tail, accelerating the traverse speed up to a speed upon normal take-up operation, pressing the unwound second bobbin against a driving roll, switching off a power supply to said independent electric motors for driving the bobbins, and then carrying out the take-up operation with a peripheral drive system.

United States Patent [191 Kuno et al.

[ Nov. 25, 1975 I YARN TRANSFER METHOD IN AN AUTOMATIC TAKE-UP MOTION[75] Inventors: Masanori Kuno, Chiryu; Tadaaki Kato, Nagoya, both ofJapan [73] Assignee: Mitsubishi Jukogyo Kabushiki Kaisha, Tokyo, Japan[22] Filed: Dec. 6, 1974 [21] Appl. No.: 530,487

[30] Foreign Application Priority Data Dec. 24, 1973 Japan 48-2432 [52]US. Cl. 242/18 A; 242/18 PW [51] Int. Cl. B65H 67/04 [58] Field ofSearch 242/18 A, 18 PW, 18 DD, 242/18 G, 25 A [56] References CitedPrimary Examiner-Stanley N. Gilreath Attorney, Agent, or FirmCushman,Darby & Cushman [57] 4 ABSTRACT In an automatic take-up motion ofperipheral drive turret type, a method of automatically transferring ayarn from a first bobbin on which said yarn has been being taken-up to asecond unwound bobbin on which said yarn is to be wound subsequently, isdisclosed herein. These first and second bobbins are mounted on a turretmechanism so as to be readily exchanged in position by rotating saidturret mechanism. This novel yarn transfer method consists of the stepsof driving said first and second bobbins with independent electricmotors, lowering a traverse speed of the yarn to a speed that is mostsuitable for formation of a transfer tail, displacing a traverse camroll with a pneumatic cylinder or other known means so as to make theyarn contact with a yarn grasping device provided at an end of thebobbins or on a bobbin holder and to make the yarn grasping device graspsaid yarn, cutting off the yarn between said yarn grasping device andthe fully wound first take-up bobbin by means of a cutter associatedwith said yarn grasping device to take-up the yarn on the second unwoundbobbin, restoring the traverse cam roll to its normal positionsimultaneously with the formation of the transfer tail, accelerating thetraverse speed up to a speed upon normal take-up operation, pressing theunwound second bobbin against a driving roll, switching off a powersupply to said independent electric motors for driving the bobbins, andthen carrying out the take-up operation with a peripheral drive system.

1 Claim, 5 Drawing Figures US. Patent Nov. 25, 1975 Sheetlof3 3,921,923

US. Patent Nov. 25, 1975 Sheet20f3 3,921,923

US. Patent Nov. 25, 1975 Sheet3of3 3,921,923

YARN TRANSFER METHOD IN AN AUTOMATIC TAKE-UP MOTION CATEGORY OF THEINVENTION This invention relates in general to improvements in anautomatic take-up motion, and more particularly to improvement in amethod of automatically transferring a yarn from a first bobbin on whichsaid yarn has been being taken-upto a second unwound bobbin on whichsaid yarn is to be wound subsequently in said automatic take-up motion.

BACKGROUND OF THE INVENTION Heretofore, the so-called automatic take-upmotions in which a yarn being taken-up on a fully wound bobbin istransferred onto an unwound bobbin without interrupting the take-upoperation and thereby the yarn can be taken-up continuously, have beenproposed. However, these automatic take-up motions in the prior art allhad difficulties in the method of transferring a yarn being taken-up toa unwound bobbin, and no satisfactory one could be obtained in respectto reliability in yarn transfer as well as formation of a transfer tail.More particularly, although the formation of the transfer tail waspossible according to the method of transferring a yarn in which afterthe yarn has been taken-up on a fully wound bobbin the yarn isdisengaged from a traverse guide and then the yarn is engaged to a yarngrasping device provided at an end of an unwound bobbin or on a bobbinholder, there was a fear that a yarn may be taken-up on the fully woundbobbin without being traversed and thus a fully wound package maypossibly get out of shape upon high speed taken-up operation, becausethe yarn was disengaged from the traverse guide. On the other hand,according to the method of transferring a yarn in which a yarn is keptinserted in a traverse guide and while traversing the yarn it is engagedto a yarn grasping device provided on an unwound bobbin, the transferoperation of the yarn could be achieved satisfactorily to a certainextent, but it was impossible to form a transfer tail because the yarnwas always traversed.

SUMMARY OF THE INVENTION The present invention has been worked out inorder to obviate the aforementioned disadvantages in the prior art, andit is a principal object of the present invention to provide a novelyarn transfer method in an automatic take-up motion, in which a transfertail can be formed and also transfer of a yarn can be achieved reliablyby continuing traverse of the yarn without disengaging the yam from atraverse guide and by carrying out transfer of the yarn while it isbeing taken-up on a fully wound bobbin.

According to one feature of the present invention, a method oftransferring a yarn in an automatic take-up motion consists of the stepsof driving bobbins with independent electric motors, lowering a traversespeed to a speed that is most suitable for formation of a transfer tail,displacing a traverse cam roll with a pneumatic cylinder or other knownmeans so as to make the yarn contact with a yarn grasping deviceprovided at an end of the bobbins or on a bobbin holder and to make theyarn grasping device grasp said yarn, cutting off the yarn between saidyarn grasping device and a fully wound take-up bobbin by means of acutter associated with said yarn grasping device to take up the yarnnewly on an unwound bobbin, restoring the traverse cam roll to itsnormal positionsimultaneously with the formation of the transfer tail,accelerating the traverse speed up to a speed upon normal take-upoperation, pressing the unwound bobbins against a driving roll,switching off a power supply to said independent electric motors fordriving the bobbins, and then carrying out the take-up operation with aperipheral drive system.

Above-mentioned and other features and objects of this invention willbecome more apparent by reference to the following description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a cross-sectional side view of an automatic take-up motionwhich practices the method according to the present invention,

FIGS. 2, 3 and 4 are diagrammatic views showing successive states in atake-up operation of a part of the apparatus in FIG. 1, and

FIG. 5 is a timing chart showing the time sequence of the actuation ofthe respective component parts in the same apparatus upon automaticallytransferring a yarn from one bobbin to'another.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT:

Referring now to the drawings, especially to FIG. 1, reference numeral 1designates a drive roll, numeral 2 designates a traverse cam roll,numeral 3 a traverse guide, and numerals 4, 4' bearings for supportingthe traverse cam roll 2, said bearings 4, 4' being slidably held withina cam box (5). Numeral 6 designates a pneumatic cylinder (having astroke of about mm) for displacing the traverse cam roll 2 and iscoupled to the bearing 4. Numeral 7 designates an electric motor fordriving the traverse cam roll 2, which is telescopically coupled to thetraverse cam roll 2 through a coupling mechanism 8. Numeral 9 designatesanother electric motor for the drive roll 1. It is to be noted that theaforementioned drive roll 1 is adapted to be pressed against a bobbin byany appropriate butting means (not shown). Reference numerals 10, 10designate bobbin,

holders held by a turret arm 11. Numerals 12, 12 designate electricmotors for accelerating the bobbins, which are contained within thebobbin holders l0 and 10, respectively, and which are connected to anexternal power supply (not shown) through wires 13 and slip rings 14.Numeral 15 designates an unwound bobbin, numeral 15 designates a fullywound bobbin, and numerals l6 and 16' designate yarn grasping devicesprovided on the respective bobbins l5 and 15. Numeral l7 designatesyarns at the opposite traverse end positions during the period when theyarn is traversed in a normal take-up operation, numeral 18 designatesyarns at the opposite traverse end positions during the period when thetraverse cam roll 2 has been displaced by actuating the pneumaticcylinder 6 so that the yarn may contact with the yarn grasping device16, numeral 19 v 15 has become fully wound, the electric motor 12contained within the bobbin holder for the unwound.

bobbin is automatically switched on to accelerate the unwound bobbin 15until it acquires such r.p.m. that its peripheral velocity becomes equalto or higher than the linear velocity of the yarn that is being wound onthe fully woundbobbin 15' (FIG. 2). Subsequently, after the rpm. of theunwound bobbin has been completely raised, the turret arm 11 is rotatedto separate the fully wound bobbin 15 from the drive roll 1 and to bringthe unwound bobbin 15 to a position just in front of the position whereit contacts with the drive roll 1 (FIG. 3). Substantially in coincidencewith the separation of the fully wound bobbin 15' from the drive roll 1,the traverse speed control device 19 is actuated to lower the traversespeed to a speed most suitable for formation of a transfer tail (30 100rpm). Since the fully wound bobbin 15 becomes not to be applied with adriving force as it leaves the drive roll 1 at this moment, in order toprevent the yarn from slackening the electric motor 12 contained withinthe bobbin holder 10 for the fully wound bobbin 15 is switched onsimultaneously with the rotation of the turret arm 11 and thereby atension in the yarn can be maintained. Then the yarn is taken-up on thefully wound bobbin l5" and traversed at a reduced traverse speed, whileit is slipping on the surface of the unwound bobbin 15 that is beingrotated at a high speed. Simultaneously with the rotation of theturretarm 1 l, the pneumatic cylinder 6 is actuated to displace thetraverse cam roll 2 by about mm so that the traverse motion may beperformed up to the position where the yarn makes contact withthe yarngrasping device 16 provided at one end of the bobbin. In this way, theyarn l8 traversed up to the position above the yarn grasping device 16is at once en-. gaged with the yarn grasping device 16 that is rotatingwith a relative velocity to the yarn, and a new take-up operation on theunwound bobbin 15 is commenced as the yarn is traversed at a reducedspeed from that end of the unwound bobbin 15 towards its centralportion. On the other hand, the yarn which has been being taken up onthe fully wound bobbin 15' is cut off by means of a cutter associatedwith the yarn grasping device. Then the commencement of the take-upoperation is detected by means of the photoelectric tube means 20, andin response to the detected signal, the pneumatic cylinder 6 is againactuated to restore the traverse cam roll 2 to its normal position, thetraverse speed control device 19 is actuated to realize a normaltraverse speed, the unwound bobbin 15 is pressed against the drive roll1, and simultaneously therewith the electric motors 12 and 12 containedwithin the respective bobbin holders 10 and 10 are switched off. Theunwound bobbin 15 is frictionally driven by the drive roll I to achievethe conventional surface drive type of take-up operation. Theabove-referred respective operations are continuously and automaticallycarried out during several seconds, and thus the transfer of the yarnhas been finished.

Now the present invention will be further explained in more detail inconnection to the following practical example:

EXAMPLE Yarn Speed: 2500m/min. Number of Ends: 1 end/bobbin holderNumber of Bobbins: l bobbin/bobbin holder Bobbin Size: Outer Diameter89mm X lnner Diameter 73mm d) X Length 340mm Traverse Length: 305mmTraverse Frequency: 700 times/min. upon normal takeup operation 60times/min. upon yarn transfer-opera tion Stroke of Displacement forTraverse Means: 20mm Maximum Wound Diameter: 250mm Yarn: nylon stretchedyarn of 420 denier Outer Diameter of Drive Roll: mm 4) Yarn GraspingDevice: a ring having a saw-tooth shaped cutter Electric Power Supplyfor Electric Motors for Drive Roll and Those Contained within BobbinHolders: 21 common power supply (The power supply for driving the fullywound bobbin uses an auto-transformer of slide type to regulate thevoltage.)

Traverse Speed Control Device: A speed control sys U tem is employed, inwhich inverter power supplies for high speed operation and for low speedoperation are I individually provided and upon yarn transfer-these,power supplies are switched from one to another to achieve speedcontrol.

With regard to the above-referred example, the time sequence of theactuation of the respective components parts can be illustrated as shownin FIG. 5. I

As described above, according to the present invention, under thecondition that an unwound bobbin asso-, w ciated with anacceleratingelectric motor is rotating at:

a peripheral velocity that is most suitable for making a yarn winditself round the bobbin as accelerated by said accelerating electricmotor, the unwound bobbin is made to contact with the yarn that is beingtaken-up on a fully wound bobbin, then the yarn travelling towards thefully wound bobbin is transferred to the unwound bobbin by actuation ofa yarn grasping device at an end vice provided at an end of the bobbinor on the bobbin f holder, to thereby achieved yarn grasping and cuttinga of the yarn. Since the yarn is being traversed at a reduced speed, itis taken-up in a spiral form having a small pitch angle from the end ofthe bobbin towards its central portion to form a transfer .tail. Thiscommencement of the take-up operation is detected by means of aphotoelectric tube or other known means,

and in response to this detected signal, the traverse means is restoredto the position upon normal take-up operation and also the traversefrequency is also restored to the frequency upon normal take-up operaition. ln addition, simultaneously with the commencement of take-upoperation of the yarn, the power supply for the accelerating electricmotor is switched off, and the take-up operation is achieved accordingto a.

surface. frictional drive system while pressing the unwound bobbinagainst the drive roll. As described,

since the yarn transfer is carried out as the yarn is being taken-up onthe fully wound bobbin while continuing the traverse of the yarn withoutdisengaging the yarn from a traverse guide, the tension in the yarn canbe maintained even upon yarn transfer and the yarn would not wind itselfround the drive roll or the Godet roll. In addition, since theperipheral velocity of the unwound bobbin upon engaging with the yarncan be adjusted to make the relative movement between the yarn graspingdevice and the yarn to a most suitable one for making the yarn winditself round the bobbin, the yarn transfer operation can be carried outin a reliable manner.

Furthermore, since the traverse speed is lowered during the yarntransfer operation, a transfer tail can be formed simultaneously withthe winding of the yarn itself round the bobbin, and by restoring thetraverse means to the position for normal take-up operation after theformation of the transfer tail has been confirmed, the yarn wound not betaken-up as overlapped on the initially formed transfer tail, and so aperfect transfer tail can be obtained. During the yarn transferoperation, the fully wound bobbin is rotating due to its own inertia, asit is separated from and not driven by the drive roll. However, in orderto maintain the tension in the yarn in a more reliable manner, thebobbin driving motor is actuated to prevent the fully wound bobbin frombeing decelerated, during the period of 2 3 seconds from the separationof the fully wound bobbin from the drive roll up to the completion ofthe yarn transfer operation.

While it is desirable for carrying out the aforementioned operations tohave an electric power supply which can independently adjust theperipheral velocities of the drive roll, unwound bobbin and fully woundbobbin, respectively, the power supplies for driving the drive roll,unwound bobbin and fully wound bobbin could be provided in common, ifthe outer diameter of the drive roll and the outer diameter of theunwound bobbin are appropriately selected (the outer diameter of thedrive roll being selected somewhat smaller than the outer diameter ofthe unwound bobbin or than twice as large as the latter), and if thenumber of poles,

output power and torque performance of the bobbin accelerating electricmotor are appropriately selected.

Since many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A method of transferring a yarn from a fully wound take-up bobbin toan unwound bobbin in an automatic take-up motion of a peripheral driveturret type, characterized by the steps of, independently rotating saidunwound bobbin, separating said fully wound bobbin from a drive rollperipherally driving said fully wound bobbin, independently rotatingsaid fully wound bobbin, lowering a traverse speed of the yarn to aspeed that is most suitable for formation of a transfer tail, displacinga traverse cam roll with a pneumatic cylinder or other known means so asto make the yarn contact with a yarn grasping device provided at an endof the unwound bobbin or on a bobbin holder of the unwound bobingrasping the yarn with said grasping device, cutting off the yarnbetween said yarn grasping device and said fully wound take-up bobbin bymeans of a cutter associated with said yarn grasping device to take-upthe yarn on said unwound bobbin, restoring the traverse cam roll to itsnormal position simultaneously with the formation of the transfer tail,accelerating the traverse speed of the yarn up to a speed for normaltake-up operation, pressing the unwound bobbin against a driving roll,switching off a power supply to the means independently driving thebobbins, and rotating said unwound bobbin with said driving roll forcarrying out the take-up operation.

1. A method of transferring a yarn from a fully wound take-up bobbin toan unwound bobbin in an automatic take-up motion of a peripheral driveturret type, characterized by the steps of, independently rotating saidunwound bobbin, separating said fully wound bobbin from a drive rollperipherally driving said fully wound bobbin, independently rotatingsaid fully wound bobbin, lowering a traverse speed of the yarn to aspeed that is most suitable for formation of a transfer tail, displacinga traverse cam roll with a pneumatic cylinder or other known means so asto make the yarn contact with a yarn grasping device provided at an endof the unwound bobbin or on a bobbin holder of the unwound bobingrasping the yarn with said grasping device, cutting off the yarnbetween said yarn grasping device and said fully wound take-up bobbin bymeans of a cutter associated with said yarn grasping device to take-upthe yarn on said unwound bobbin, restoring the traverse cam roll to itsnormal position simultaneously with the formation of the transfer tail,accelerating the traverse speed of the yarn up to a speed for normaltake-up operation, pressing the unwound bobbin against a driving roll,switching off a power supply to the means independently driving thebobbins, and rotating said unwound bobbin with said driving roll forcarrying out the take-up operation.